Description

The library routines described on this page are part of the
Network Selection component. They provide the application access to the system network
configuration database, /etc/netconfig. In addition to the routines for accessing the
netconfig database, Network Selection includes the environment variable NETPATH (see environ(5)) and the
NETPATH access routines described in getnetpath(3NSL).

getnetconfig() returns a pointer to the current entry in the netconfig
database, formatted as a struct netconfig. Successive calls will return successive netconfig
entries in the netconfig database. getnetconfig() can be used to search the
entire netconfig file. getnetconfig() returns NULL at the end of
the file. handlep is the handle obtained through setnetconfig().

A call to setnetconfig() has the effect of ``binding'' to or ``rewinding''
the netconfig database. setnetconfig() must be called before the first call to
getnetconfig() and may be called at any other time. setnetconfig() need not
be called before a call to getnetconfigent(). setnetconfig() returns a unique
handle to be used by getnetconfig().

endnetconfig() should be called when processing is complete to release resources for
reuse. handlep is the handle obtained through setnetconfig(). Programmers should be aware,
however, that the last call to endnetconfig() frees all memory allocated by getnetconfig()
for the struct netconfig data structure. endnetconfig() may not be called before setnetconfig().

getnetconfigent() returns a pointer to the struct netconfig structure corresponding to netid. It
returns NULL if netid is invalid (that is, does not name
an entry in the netconfig database).

freenetconfigent() frees the netconfig structure pointed to by netconfigp (previously returned by
getnetconfigent()).

nc_perror() prints a message to the standard error indicating why any of
the above routines failed. The message is prepended with the string msg
and a colon. A NEWLINE is appended at the end of the
message.

nc_sperror() is similar to nc_perror() but instead of sending the message
to the standard error, will return a pointer to a string that
contains the error message.

nc_perror() and nc_sperror() can also be used with the NETPATH access routines
defined in getnetpath(3NSL).

Return Values

setnetconfig() returns a unique handle to be used by getnetconfig(). In the
case of an error, setnetconfig() returns NULL and nc_perror()
or nc_sperror() can be used to print the reason for failure.

getnetconfig() returns a pointer to the current entry in the netconfig() database,
formatted as a struct netconfig. getnetconfig() returns NULL at the end
of the file, or upon failure.

endnetconfig() returns 0 on success and -1 on failure (for example, if
setnetconfig() was not called previously).

On success, getnetconfigent() returns a pointer to the structnetconfig
structure corresponding to netid; otherwise it returns NULL.

nc_sperror() returns a pointer to a buffer which contains the error message
string. This buffer is overwritten on each call. In multithreaded applications,
this buffer is implemented as thread-specific data.